Bistable pneumatic logic element and valves



May 30, 1967 J. E. ROCHTE BISTABLE PNEUMATIC LOGIC ELEMENT AND VALVES Filed Nov. 12, 1963 FIG. 4

FIG. 8

4 Sheets-Sheet 3 FIG. 3 b

FIG. 5

INVENTOR.

JERRY E. ROCHTE BY ATTORNEY May 30, 1967 J. E. 'ROCHTE BISTABLE PNEUMATIC LOGIC ELEMENT AND VALVES 4 Sheets-Sheet Filed Nov. 12, 1965 W. M Q 3 00000 :H 6 o 0 o o 0 B 4 O O 5 42 w FIG. 6

FIG. 70

FlG.7b

INVENTOR. JERRY E. ROCHTE ,Zbfl/k ATTORNEY United States Patent 3,322,148 BISTABLE PNEUMATIC LOGIC ELEMENT AND VALVES Jerry E. Rochte, Long Beach, 'Calif., assignor to Beckman Instruments, Inc., a corporation of California Filed Nov. 12, 1963, Ser. No. 322,879 13 Claims. (Cl. 137596.14)

This invention relates generally to a pneumatic digital logic element and more particularly to a pneumatic memory element in the form of a bistable flip-flop wherein the element may be pneumatically set or reset into one of two states and Will remain in that state until transferred to the other state under the influence of a pneumatic control signal. This invention further relates to a 4-way valve incorporating the digital logic element as a control element and wherein a continuous pneumatic output may be provided at either of two output lines as a result of a momentary pneumatic control signal.

In the past the pneumaticindustry has performed the operations performed by this invention by use of double acting air operated valves used either in conjunction with pistons or diaphragms connected to O-ring sliding valves, or through the utilization of sliding plates instead of the O-ring valve. More recently, fluid turbulence amplifier techniques have been utilized. Each of these methods are relatively difficult to implement due to the precision and number of moving parts required. These devices are difficult to manufacture and in many cases relatively expensive- Further, such devices often require units of considerable size and consume large quantities of gas under pressure.

It is, therefore, a principal object of'this invention to provide a new and improved pneumatic memory element which may be set or reset to one of two states and which will remain in that state until actuation by a pneumatic control signal.

Another object is to provide a pneumatic memory .element which is simple of manufacture and which does not require the precision or number of moving parts characteristic of the prior art devices.

A further object of the invention is the provision of a pneumatic memory element which is controlled by the momentary creation of a differential pressure therein to deflect a pressure responsive element to place the memory element in one of two states and wherein the pressure responsive element operates to maintain the' differential pressure within the memory element such that the element remains in one state until actuation by another control signal.

Still another object is to provide a valving system incorporating a pneumatic memory element wherein a pneumatic power stream may be switched between one of two outputs under the influenceof a small pneumatic control signal.

Yet another object is the provision of a pneumatic valving system which may be conveniently utilized to switch a pneumatic power stream wherein a pneumatic power output may be controlled under the influence of a small pneumatic control signal.

Another object of the invention is the provision of a pneumatic 4-way valve wherein a pneumatic power stream may be controlled under the influence of a small pneumatic control stream and wherein the entire system may be molded and assembled as a small module.

The pneumatic memory element of the present invention generally contemplates a pair of chamber means separated by a pressure responsive element, each of the chamber means having an inlet for connection to a source of gas under pressure. Through the use of any suitable control device a differential pressure may be created between the chamber means so as to deflect the pressure respon- 3,322,148 Patented May 30, 1967 ice sive element into the chamber means having the lowest pressure. Deflection of the pressure responsive element operates to cut off the inlet from the pneumatic power supply such that the pressure in the chamber remains at a lower pressure and the pressure responsive element remains in the deflected position even with changes in condition of the controlling device. The pressure responsive element remains in the deflected condition until the differential pressure between the two chamber means is reversed under the influence of the controlling device and the pressure responsive element is flipped to the other condition to cut off the input to the other chamber means. The element will remain in the new position due to the differential pressure maintained between the chamber means by the element having cut off one of the inputs to one of the chamber means until subsequent actuation under the influence of the control device.

The 4-way valve of the present invention generally contemplates the use of the aforedescribed pneumatic memory element as a controlling mechanism for the control of a pneumatic power stream. In the valving system addi-. tional chamber means are utilized each having a pressure responsive element. Each of these elements assume, under the control of the output of the memory element, one of two positions. In one position the particular pressure responsive element cuts off a power inlet to one of the chamber means and in the other condition this inlet remains open. By properly connecting the inlets and outlets of each of the chamber means, a pair of outputs may be provided wherein in one stable condition one of the outputs is at a high pressure while the other is at a low pressure and in the other stable condition the second output is at a high pressure while the first output is at a low pressure. 1

Other novel details of construction and arrangement of parts and other objects and attendant advantages of the present invention will be more readily appreciated by those skilled in the art as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the several figures thereof and wherein:

FIG. 1 is a schematic diagram of one illustrative embodiment of a pneumatic memory element in the form of a pneumatic bistable flip-flop;

FIG. 2 is a schematic diagram of an illustrative'embodiment of a 4-way valve incorporating the pneumatic memory device of FIG. -1;

FIG. 3a and FIG. 3b illustrate mating halves of a module and together form one illustrative method of implementing the schematic diagram of FIG. 2;

FIG. 4 illustrates the module of FIG. 3 in assembled form with that portion taken along line 4-4 of FIG. 3 broken away;

FIG. 5 illustrates a schematic diagram of a second exemplary embodiment of a pneumatic memory element in the form of a pneumatic bistable flip-flop;

FIG. 6 illustrates a schematic diagram of one illustrative embodiment of a 4-way valve incorporating the pneu matic memory element of FIG. 5;

FIGS. 7a and 7b illustrate mating halves of a module and together form one illustrative method of implementing the valving system of FIG. 6;

FIG. 8 is a cross-sectional view of the module of FIG. 7 in assembled form taken along line 88 of FIG. 7;

FIG. 9 illustrates a schematic diagram of an exemplary embodiment of a 4-way valve wherein pneumatic power from one source may be utilized to control the flow of power from a second source; and

FIG. 10 is a schematic diagram of an illustrative embodiment of a 2-way valve incorporating the pneumatic logic element of FIG. 1.

Referring now to FIG. 1 there is illustrated one illustrative embodiment of a pneumatic memory element which may be utilized in any pneumatically actuated system and which, after initial actuation, possesses two stable states. The memory element has a pair of chamber means generally indicated by the reference numeral 10. The first chamber means comprises a first portion 11 and a second portion 12 interconnected by a conduit 13. The second chamber means has a first portion 15 and a second portion 16 interconnected by a conduit 17. The two chamber means are separated by pressure responsive means which in the illustrative embodiment of FIG. 1 may take the form of a pair of resilient diaphragms; diaphragm '18 separating the first portion 11 of the first chamber means from the second portion 16 of the second chamber'means and diaphragm 19 separating the second portion 12 of the first chamber means from the first portion 15 of the second chamber means. Gas under pressure may be supplied to pOWer input conduit 21 which is respectively connected'to power input conduits 22 and 23 which are somewhat restricted with respect'to the other conduits within the system. Conduit 22 terminates within the first portion 11 of the .first' chamber means and conduit 23 terminates within the first portion 15 of the second chamber means. Control input conduits 24 and 25 connect respectively the second portion 12 of the first chamber means and the second portion 16 of the second chamber means to any suitable control means such, for example, as 2-Way valves 26 and 27. Output conduit 29 connected to the second portion 12 of the first chamber means is provided for tak ing an output pressure therefrom and may be connected to any suitable high impedance type utilization device 30. In like manner, output conduit 31 is connected to the second portion 16 of the second chamber means and is provided for taking a second output from the memory element and may be connected to any suitable device such as utilization device 32. I

In operation control valves 26 and 27 are normally closed and are opened to place the memory element into one or the other of its stable states. Let it be assumed that both control elements 26 and 27 are initially closed and gas under pressure is being supplied through input conduit 21. Initially, pressure responsive means 18 and 19 will assume a position midway between the solid and dotted lines illustrated and gas under pressure will be supplied through each of conduits 22 and 23. Pressure in the first and second portions 11 and 12 of the first chamber means will equalize due to the interconnection by conduit 13 as will the pressure in the first and second portions 15 and 16 respectively of the second chamber means due to the interconnection of these two portions by conduit 17. Since gas under like pressure is being supplied to first portions 11 and 15 of each of the chamber means and since second portions 12 and 16 are interconnected therewith the pressure on each side of pressure responsive means 18 and 19 is equal and they will remain in the neutral position. Since the pressure in second portions 12 and 16 is equal, the pressure in output conduits 29 and 31 is equal.

Let it now be assumed that the valve comprising control element 26 is momentarily opened such that the second portion 12 of the first chamber means is vented to the atmosphere or to some other low pressure area. Pressure in the second portion 12 of the first chamber means drops as does the pressure in the first portion 11 by virtue of the interconnecting conduit 13. A differential pressure is now created between the first and second chamber means, the first portion 11 of the first chamber means being at a low pressure and the second portion 16 of the second chamber means being at a high pressure. Under this condition pressure responsive means 18 is deflected to the position illustrated by the solid line which is arbitrarily designated the set position and operates to close power inlet conduit 22. A like differential pressure is created between second portion 12 of the first chamber means and the first portion 15 of the second chamber means deflecting pressure responsive element 19 away from the inlet conduit 23. Valve 26 may now be closed and pressure responsive elements 18 and 19 will remain in the condition illustrated by the solid line due to the differential pressure between the first and second chamber means, the high pressure in the of the condition of control element 26. Since the second portion 12 of the first chamber means is at a low pressure the pressure in output conduit 29 is likewise low and, due to the high pressure in the second portion 16 of the second chamber means, the output pressure in output conduit 31 is at a high value. This diflerential pressure between the outputs 29 and 31.will remain until actuation of control ele- V r'nent 27. a

Let it now be assumed that control element 26 is closed and control element 27 is momentarily opened. venting the second portion 16 of the second chamber means to the atmosphere or any other low pressure area. The pressure in the second portion 16 of the second chamber means drops to the same pressure present in the first portion 11 of the first chamber means and pressure responsive element 18 tends to return to its neutral positiomInlet conduit 22 to the first portion 11 of the first chamber means is then opened and the pressure in the first portion 11 and the" second portion 12 of the first chamber. means begins to increase deflecting pressure responsive element 18 to the position indicated by the dotted line. Since the first portion 15 of the second chamber means is now vented to a low pressure area by virtue of conduit 17 i 7 closes the power inlet conduit 23 to the first portion 15- 1 of the first chamber means and the first chamber means remains at this low pressure condition. Since portion 15 of the second chamber means is at a .low pressure and the 3 second portion 12 of the first chamber means is at'a high pressure element 19 remains in the reset condition. Pressure responsive elements 1 8 and 19 will remain in the reset condition regardless of the condition of control element 27 so long as control element 26 remains closed. In the reset condition a high pressure exists in the output conduit 29 while a low pressure now exists in output conduit 31.

Referring now to FIG. 2 there is illustrated a schematic diagram of a 4-way valve embodying the pneumatic memory element of FIG. .1. The elements of the pneumatic memory previously 'described in connection With FIG. 1 contain like numerals and will not be described except in connection with the operation of the system.

The 4-way valve system comprises eight additional chamber means 38-41 and 4346. Cooperating pairs of the chamber means are separated by pressure. responsive elements 4851 respectively. Each of chamber means 38' 41 have a respective inlet conduit 53-56 positioned in such a manner as to be closed by the respective pressure responsive element, inlet conduits 53 and 54 being closed when pressure responsive elements 48 and 49 are in the set condition as indicated by the solid lines and inlet conduits 55 and 56 being closed when respective pressure re-' sponsive elements 50 and 51 are in the reset condition as indicated by the dotted lines. Chamber means 38 and 41 have respective outlet or exhaust conduits 58 and 59 to exhaust these chamber means to the atmosphere or any other low pressure area. Chamber means 39 has an outlet conduit 60 connected to inlet conduit 56 of chamber means 41 and chamber means 40 has an outlet conduit 61 connected to inlet conduit 53 of chamber means 38. Output conduit 29 of the pneumatic memory is connected pressure in the second chamber means remains at a high value. As is obvious, this condition will remain regardless to inlet conduit 62 of chamber means 45 and to inlet conduit 63 of chamber means 46. Outlet conduit 31 of the pneumatic memory is connected to inlet conduit 65 of chamber means 44 and to inlet conduit 66 of chamber means 43. Inlet conduit 53 of chamber means 38 and outlet conduit 61 of chamber means 40 are connected to a valve output conduit 67. Inlet conduit 56 of chamber means 41 and outlet conduit 60 of chamber means 39 are connected to a second valve output conduit 68. Output conduits 67 and 68 may be connected to any suitable utilization device such as the pneumatic cylinder 69.

In operation, let it be assumed that the pneumatic memory element or bistable flip-flop is in the set condition under the influence of control element 26 such that the pressure responsive elements 18 and 19 are as indicated in FIG. 2. As has been previously described, under this condition the pressure in output conduit 31 is high and the pressure in output conduit 29 is low. Since chamber means 38 is exhausted to the atmosphere via exhaust or output'conduit 58 the high pressure created in chamber means 43 deflects the pressure responsive element 48 to the position indicated by the solid lines and closes inlet conduit 53. Since the output in conduit 29 of the memory element is at allow pressure, pressure responsive element 51 remains in the neutral position illustrated and inlet conduit 56 of chamber means 41 is open to a low pressure area due to output conduit 59. The gas pressure input through power input conduit 54 to chamber means 39 is therefore initially exhausted to the atmosphere via the output conduit 60, input conduit 56 to chamber means 41 and exhaust conduit 59. Therefore, chamber means 39 assumes a low pressure and the high pressure output from memory output conduit 31 to the inlet 65 creates a high pressure in chamber means 44 thereby deflecting pressure responsive element 49 to close inlet conduit 54. Due to the low pressure in output conduit 29 of the memory element, chamber means 45 is at a low pressure while chamber means 40 is held at a high pressure due to the input from the pressure source via input conduits 21 and 55. Thus, pressure responsive element 50 assumes a position illustrated by the solid line. The high pressure of chamber means 40 is connected via output conduit 61 to input conduit 53 of chamber means 33 which is closed by pressure responsive element 48 in the set condition. This high pressure output is also supplied via valve output conduit 67 to one side of pneumatic cylinder 69. The other side of pneumatic cylinder 69 is connected to valve output conduit 68 which is in turn connected to input conduit 66, chamber means 41 and exhaust conduit 59 to the atmosphere or other low pressure area. Outlet conduit 60 of chamber means 39 also assumes this low pressure by virtue of the inlet conduit 54 being closed by pressure responsive element 49. It is thus seen that the entire pressure from the power source connected to power input conduit 21 is transferred via conduits 55, 61 and 67 to one side of the utilization device. The other side of the utilization device is connected to a low pressure area via conduits 68, 56 and 59 and the movable piston therein will be driven to the right as viewed in FIG. 2.

Let it now be assumed that control element 26 is in the closed condition and control element 27 is momentarily opened. Pressure responsive elements 18 and 19 will assume the reset position as indicated by the dashed lines for the reasons hereinbefore described in connection with FIG. 1. A high pressure is now created in output conduit 29 while output conduit 31 assumes a low pressure condition. With the high pressure created in chamber means 45 and 46 respectively pressure responsive elements 50 and 51 are deflected to the reset condition illustrated by the dashed lines and close inlet conduits 55 and 56. With the low pressure created in chamber means 43 and 44 respectively the pressure responsive elements 48 and 49 assume the reset condition indicated by the dotted lines and open inlet conduits 53 and 54. In

the reset condition fluid under pressure is supplied via inlet conduit 21, conduit 54 to chamber means 39, via outlet conduit 60 thus creating a high pressure condition in valve outlet conduit 68 inasmuch as inlet conduit 56 of chamber means 41 is closed by deflection of element 51. Outlet conduit 67 assumes a low pressure condition by virtue of its connection through inlet conduit 53 to chamber means 33 and the exhaust conduit 58 also connected to chamber means 38. Thus a high pressure is created in valve output conduit 68 and a low pressure in valve outlet conduit 67 and the movable piston in the pneumatic cylinder 69 will be driven to the opposite side of the cylinder. As is obvious the respective outputs of the valve will remain until subsequent actuation by the other control element to change the state of the pneumatic memory.

Referring now to FIGS. 3a and 317 there is illustrated mating halves of a module forming the 4-way valve schematically indicated in FIG. 2 and like numbers have been utilized to designate corresponding elements. The portion illustrated in FIG. 3b is placed atop that portion illustrated in FIG. 3a without changing its relative orientation to FIG. 3a with pressure responsive elements in the form of resilient diaphragms interposed between the module as more fully described hereinafter to separate the various chamber means. In the subsequent description the inner faces should be interpreted to mean those faces of the two halves of FIGS. 3a and 3b which are pressed together to form the entire module, i.e., the upper surface 71 of FIG. 3a and the lower surface 72 of FIG. 3b.

The first chamber means of the pneumatic memory has its first portion 11 formed in the half module illustrated in FIG. 3a and its second portion 12 formed in the half module illustrated in FIG. 311 connected by conduits 13a (FIG. 3a) and 131) (FIG. 3b) which are sealed at the inner faces of the two halves of the module by O-ring 73. The second chamber means has its first portion 15 and a second portion 16 similarly formed and intercom nected by conduits 17a and 17b sealed at the inner faces by an O-ring 74. Conduit 21 formed in the half of the module illustrated in FIG. 3a is adapted to be connected to a source of fluid under pressure and is connected to the first portion 11 of the first chamber means by input conduit 22 and to the first portion 15 of the second charn ber means by input conduit 23.

Referring briefly to FIG. 4 there is illustrated a crosssection-al view of the module taken along lines 4-4 of FIGS. 3a and 3b showing the module in its assembled form and the first chamber means in greater detail, it being understood that each of the other chamber means are similarly formed. The first portion 11 of the first chamber means and the second portion 16 of the second chamber means are separated by resilient diaphragm 18 positioned adjacent the inner faces of the module and serve not only to seal the input conduit 22 as has been hereinbefore described but also to seal the chamber means at the inner faces of the two halves of the module. Input conduit 22 terminates in an inwardly projecting nipple 75 closely adjacent the resilient diaphragm 18 which is shown in FIG. 4 in its normal position. When a differential pressure is developed between the first portion 11 and the second portion 16 of the respective chamber means such that a higher pressure occurs in the second portion 16 diaphragm 18 is deflected as illustrated by the dotted lines to seal conduit 22 along the end surface of nipple 75. When the differential pressure is reversed the resilient diaphragm 18 returns to its normal position or is flexed into the second portion 16 of the second chamber means but does not operate to seal the inner connecting conduit 17b.

Referring again to FIGS. 3a and 3b control input conduit 24 is adapted to be connected to any suitable control element and terminates within the first portion 11 of the first chamber means. By virtue of conduits 13a and 13b 7 the control means is also connected to the second portion 12 of the first chamber means as has been schematically illustrated in FIG. 2. In like manner control input conduit 25 is likewise adapted to be connected to any-suitable control element and terminates in the first portion 15 of the second chamber means. Output conduit 29 is connected to the second portion 12 of the first chamber means and output conduit 31 is connected to the second portion 16 of the second chamber means. The portion of FIGS. 3a and 3b thus described complete those elements necessary for the formation of the pneumatic memory element in the form of a pneumatic bistable flip-flop after the teachings of this invention. It should be understood that the second portion 12 of the first chamber means and the first portion 15 of the second chamber means are separated and sealed by a diaphragm in the same manner as illustrated in FIG. 4. V 7

To complete the 4-way valving system of FIG. 2 the portion of the module illustrated in FIG. 3a has formed therein chamber means 38, 39, 40 and 41 and the portion of the module illustrated in FIG. 317 has formed therein mating chamber means 43, 44, 45 and 46. Respective pressure responsive elements (not shown) separate the cooperating pairs of chamber means as indicated in FIG. 2 and also serve to seal the various chamber means at the inner faces 71 and 72. Chamber means 38 and 41 have exhaust conduits 58 and 59 respectively adapted to exhaust these chamber means to the atmosphere or to be connected to an area of low pressure. Input conduit 53 of chamber means 38 is connect-ed to the exhaust conduit 61 of chamber means 40 and valve output conduit 67 adapted to be connected to any suitable utilization means is also connected to the chamber means 40 thereby completing one 'half of the output of the valving system as illustrated in FIG. 2.

In like manner input conduit'56 to chamber means 41 is connected to the exhaust conduit 60 of chamber means 39 which also has connected thereto the second valve output conduit 68 thereby completing the second valve output of the system of FIG. 2. Power source input conduit 21 is connected to input conduit 55 of chamber means 40 and to input conduit 54 of chamber means 39.

It should be understood that each of the input conduits 53, 54, 55 and 56 terminate in nipples located closely adjacent to the respective diaphragms such that the diaphragm upon deflection will close the conduit in the same manner as illustrated in FIG. 4.

Referring now to FIG. 3b the memory output conduit 29-is connected to input conduit 63 of chamber means 46 and to input conduit 62 of chamber means 45. Input conduits 65 and 66 are in similar manner connected to the second portion 16 of the second chamber means of the memory element, input conduit 66 being directly connected to output conduit 31 and input conduit 65 being connected to the second portion 16 via conduit 17b. It is obvious to those skilled in the art that these connections are in all respects equivalent to those illustrated in the schematic diagram of FIG. 2 and the operation thereof is the same. It should be further understood that input conduit 65 could be as well directly connected to the input conduit 66 omitting the connection to conduit 17b.

Referring now to FIG. there is illustrated a schematic diagram of a second illustrative embodiment of the pneumatic memory element of the invention in the form of a pneumatic bistable flip-flop. The memory element generally comprises a first chamber means 101 and a second chamber means 102 separated and sealed one from the other by a pressure responsive element 103 which may conveniently take the form of a deflectable resilient diaphragm. Power input conduit 104 is adapted to be connected to any'suitable source of fluid under pressure and is connected to memory input conduits 106-109. Input conduits 106 and 107 terminate within the first chamber means 101, input conduit 106 terminating adjacent the pressure responsive element 103 such that this input is closed when the element is in the set position as indicated by the solid line. Input conduit 107 terminates Within the chamber in a position so as to be unrestricted by element 103 in either of its positions. In a similar manner, input conduit 108 tenminates within the second cham- 'ber means 102 in such a manner as to be closed when the pressure responsive element 103 is in the reset position as indicated by the dashed lines while conduit 109 terminates within the second chamber means 102 -in such a manner as to be unrestricted by the diaphragm in either of its positions. Input conduits 10 6 and 108 are somewhat larger in diameter than input conduits'107 and 109 and output conduits 111 and 112 such that the rate of volume flow of fluid through these two conduits is. greater than the rate of volume flow through conduits 107,

109, 111 and 112. Control conduits 111 and 112 respectively originate in first chamber means 101 and second chamber means 102 and are connected to any suitable control elements 113 and 114 respectively. Memory output conduit 115 connected to the first chamber means 101 a is adapted to be connected to any suitable utilization device 116 and memory output conduit 117 connected to second chamber means 102 is likewise adapted to be connected to any suitable utilization device 118.

In operation the control elements 113 and 114 may be operated either normally open or normally closed. Let it be assumed for the purposes of explanation that the control elements 113 and 114 are norm-ally open exhausting the chamber means 101 and 102 to the atmosphere or any other low pressure area and are closed to place the memory element in the set of reset condition.

Assume further that control elements 113 and 114 are open and that gas under pressure is being supplied to input conduit 104. Initiailly, pressure responsive element 103 will assume a neutral position midway between the input conduits 106 and 108 since the pressure in chamber means 101 and 102 will be substantial-ly equal. Let it now be assumed that control element 114 is momentarily closed. The pressure in chamber means 102 increases to deflect the pressure responsive element 103 to the set position as illustrated by the solid line. In this position the inlet of input conduit 106 is closed and the pressurein chamber means 101 decreases since the rate of volume flow through inlet 101 and exhaust outlet 111 is substantially equal. It is obvious that control element 114 may now be openedrand the differential pressure existing be-' tween chamber means 101 and 102-will remain holding element 103 in the set position by virtue of the relative sizes of the conduits 109, 108 and 112.

If now control element 113 is momentarily closed the. pressure within the chamber means 101 increases until.

the pressure responsive element 103 is deflected to the reset condition as illustrated by the dashed lines thereby closing input conduit 108. It is also obvious that the pressure responsive element will remain in the reset condition until actuation of control element 114 irrespective of the condition of control element 113.

The differential pressure existing between the chamber means 101 and 102 is supplied to output conduits 115 i and 117 it being obvious that in the set condition a high pressure output exists in conduit 117 and a low pressure output in conduit 115 and in the reset condition a high 123 each having an input conduit 125-128 respectively and an exhaust conduit -133 respectively. Each of chamber means 120-123 are sealed by any suitable pressure responsive elements -138 respectively. Located adjacent the inner surface of pressure responsive elements spectively which are urged away from contact with their respective input conduits 125-128 by compression spring means 145-148. Memory output conduit 115 is connected to conduits 150 and 151 located closely adjacent the external surface of pressure responsive elements 137 and 138 respectively. Memory output conduit 117 is connected to conduits 152 and 153 which terminate closely adjacent the pressure responsive elements 135 and 136 respectively. Input conduit 125 of chamber means 120 is connected to the exhaust conduit 132 of chamber means 122 and each of these conduits is connected to a valve output conduit 155. Similarly, input condiut 128 of chamber means 123 is connected to exhaust conduit 131 of chamber means 121 and each of these conduits is connected to a second valve output conduit 156. Input conduits 126 and 127 of chamber means 121 and 122 respectively are each connected to input conduit 104. Exhaust conduits 130 and 133 of chamber means 120 and 123 respectively are exhausted to the atmosphere or connected to any other suitable low pressure area. I

In operation as has been hereinbefore described in connection with FIG. When the pneumatic memory element is in the set condition a high pressure exists in chamber means 102 and a low pressure in chamber means 101. The pressure in chamber means 102 is suflicient to defiect the pressure responsive elements 135 and 136 pressing the input conduit cut off means 140 and 141 against the force exerted by compression spring means 145 and 146 to engage the cut off means with their respective input conduits 125 and 126 thereby closing these conduits. The low pressure in chamber means 101 of the memory element is not sufficient to deflect the pressure responsive elements 137 and 138 against the force of compression springs 147 and 148 and the input conduits 127 and 128 remain open.

Gas under pressure is passed from the power supply connected to conduit 104 to input conduit 127 of chamber means 122 which is open due to the low pressure existing in the first chamber means 101 of the memory element. The high pressure existing in chamber means 102 is connected by the exhaust conduit 132 to the input conduit 125 of chamber means 120 which is closed by element 140 under the operation of the pressure responsive means 135 in response to the high pressure existing in memory chamber means 102. This high pressure is also connected to the valve output conduit 155 and may be utilized to operate any suitable utilization device such as the double acting piston 157.

Gas under pressure is also supplied to input conduit 141 of chamber means 121 which has been closed by pressure responsive element 136 operating in response to the high pressure existing in chamber means 102 of the memory element in the set condition. Chamber means 121 is thus under a low pressure condition by virtue of exhaust conduit 131 being connected to input conduit 128 which is open when the memory element is in the set condition, chamber means 123 being exhausted to a low pressure area by exhaust conduit 133. Valve output conduit 156 is also connected to chamber means 123 and thus a low pressure exists at this output. Therefore, when the memory element is in the set condition a high pressure exists at output conduit 155 and a low pressure at output conduit 156 and the piston of utilization means 157 may be driven to the right as illustrated in FIG. 6.

Let it now be assumed that control element 113 is operated to place the memory element in the reset condition as illustrated by the dotted line, pressure responsive element 103 closing input conduit 108. Under this condition a high pressure exists in chamber means 101 and a low pressure exists in chamber means 102. The low pressure in chamber means 102 allows compression spring means 145 and 146 to open input conduits 125 and 126 and the high pressure in chamber means 101 causes deflection of pressure responsive elements 137 and 138 to close input conduits 127 and 128. Under this condition a high pressure exists in valve output conduit 156 by virtue of the power source connected to the input conduit 104 via input conduit 126, exhaust conduit 131 to valve output conduit 156, input conduit 128 having been closed under the influence of pressure responsive element 138. In the reset condition input conduit 127 is closed and input conduit is open thereby exhausting valve output conduit 155 to a low pressure area via exhaust conduit of chamber means 120. Thus, in the reset condition a high pressure exists in output conduit 156 and a low pressure in output conduit 155 and the pressure responsive piston or utilization means 157 may be driven to the left as illustrated in FIG. 6.

Referring now to FIGS. 7a and 7b there is illustrated mating halves of a module forming the 4-way valve schematically illustrated in FIG. 6 and wherein like numbers have been utilized to designate corresponding elements. That portion illustrated in 7b is placed atop that portion illustrated in FIG. 7a without changing its relative orientation with respect to FIG. 7a. A single continuous resilient diaphragm may conveniently be placed between the modules to form the pressure responsive elements -138 of FIG. 6 and has three apertures therein mating with conduits 104, and 156 of FIG. 7a and FIG. 7b, such that these conduits form a continuous passage between the modules and are sealed at the inner faces thereof. In the subsequent description the inner faces should be interpreted to mean those faces of the two halves of FIGS. 7a and 7b that are pressed against the diaphragm to form the entire module, i.e., the upper surface 158 of FIG. 7a and the lower surface 159 of FIG. 7b which are most clearly indicated in FIG. 8 adjacent the diaphragm 160. It should be understood that separate pressure responsive elements may be utilized in a manner similar to that described in connection with FIGS. 2-4 in place of the single continuous diaphragm.

Referring now to FIG. 711 there is formed a chamber means 101 having the inlet conduit 106 terminating closely adjacent to the inner face 158 and an inlet conduit 107 terminating at the lower surface of the chamber means. Inlet conduit 106 and inlet conduit 107 are each connected to power source input conduit 104 which is adapted to be connected to a source of fluid under pressure. Conduit 111 terminates within chamber means 101 and is adapted to be connected in any suitable manner to any suitable control element and the rear surface of the module.

The second chamber means 102 is formed in the half of module illustrated in FIG. 7b and has fluid input conduits 108 and 109 also connected to input conduit 104, the diaphragm interposed between the inner faces 158 and 159 having an aperture therein to allow conduit 104 to form a continuous passage between the mating halves of the module, Control conduit 112 terminates within the chamber means 102 and is brought to the rear surface of the module half illustrated in FIG. 7b and adapted for connection to any suitable control element. The internal configuration of the memory element is best illustrated in FIG. 8 wherein the pressure responsive element 103 of the schematic diagram of FIG. 6 is formed by a portion of the continuous membrane or diaphragm 160 interposed between the inner faces 158 and 159. The resilient diaphragm is shown deflected against the end of input conduit 106 thereby closing this conduit which is the position of the diaphragm when the memory element is in the set condition.

Chamber means 120 and 121 are formed in the module half illustrated in FIG. 7a, the exhaust conduit 130 connecting the chamber means 120 to the outer surface of the module for exhausting the chamber .to the atmosphere or for connection to any other suitable .low pressure area. Input conduit 126 of chamber means 121 is connected to conduit 104 which is the power input conduit to the module. Chamber means 122 and 123 are formed in the half modules illustrated in FIG. 7b, input conduit 127 of chamber means 122 being connected to the power input conduit 104 and chamber means 123 being exhausted to the atmosphere or any other suitable low pressure area via conduit 133.

The output from memory chamber means 102 is taken along conduits 152 and 153 which terminate at the inner face 159 directly opposite the chamber means 121 and 120, respectively, as best illustrated in FIG. 8. In like manner the output from chamber means 101 of the memory element is taken along conduits 150 and 151 which terminate at the inner face 158 directly opposite the chamber means 122 and 123. Interposed between the memory element outputs 150-153 and their respective oppositely disposed chamber means is the continuous diaphragm 160,

Disposed within chamber means 120 is the input conduit cut oif means 140 which, as illustrated in FIG 8, may conveniently take the form of a movable piston of any suitable material. The input conduit cut off means 140 is urged away from the end of conduit 125 by compression spring means 145 thus maintaining the input conduit normally open. Upon an increased pressure output from one of the memory chamber means such, for example, as the increased pressure created in chamber means 102 when the memory element is in the set condition, the diaphragm 160 located adjacent the chamber means 120 and 121 is deflected under the increased pressure in output conduits 152 and 153 moving the input conduit cut off means 140 and 141 against the force of compression spring means 145 and 146 to close input conduits 125 and 126.

Referring again to FIGS. 70 and 7b chamber means 122 is connected by exhaust conduit 132 to the valve output conduit 155. Input conduit 125 of chamber means 120 is likewise connected to valve output conduit 155, conduit 155 being adapted to be connected to any suitable utilization means. In a similar manner chamber means 121 is exhausted through conduit 131 to the second valve output conduit 156 also having input conduit 128 of chamber means 123 connected thereto. It should 'be understood that the diaphragm has a pair of aper- As has been previously stated the embodiment of the 7 memory element illustrated in FIG. may by proper design be operated with control elements 113 and 114 normally closed. Referring briefly to FIG. 8 power input conduits 106 and 108 are formed in nipples 162 and 163 respectively which project into chamber means 101 and 102 and terminate closely adjacent the pressure responsive element 160, Since the only force tending to move the diaphragm is the pressure exerted on the diaphragm times the area exposed to the pressure it is obvious that in either the set or the reset condition that the area within the respective chamber means exposed to pressure is different due to the wall thickness of the nipples 162 and 163. Thus, in the set position as illustrated in FIG. 8 the area exposed to pressure within chamber 101 is less than the area exposed to pressure in chamber 102 thus the force tending to hold the diaphragm against the nipple 162 is greater than the force tending to move the diaphragm away from the nipple even though the pressures within the two chambers are equal.

Referring now to FIG. 9 there is illustrated a schematic diagram of an alternative embodiment of the 4-way valve similar to that illustrated in FIG. 2 but wherein one power source P may be utilized to switch the flow of a second pneumatic stream P The schematic of FIG. 9 is similar to that of FIG. 2 except that the power input conduits 22 and 23 of the pneumatic memory element are connected to a source of gas P while input conduits 54 and 55 are matic cylinder as illustrated but may be any other device connected to a source of gas P Thus source P furnishes the power for operation of the valve which may be utilized to switch the flow of gas from source P to either of valve output conduits 67 or 68. Such a system has the advantage that an inexpensive power source may be utilized for P to provide the control power for the valve Without contamination or utilization of the gas supplied from source P For example, in chromatographic operations it is desirable to switch the carrier gas through various paths within the system. The carrier gas is usually a relatively expensive inert gas, such as helium. Utilizing the embodiment of FIG. 9 compressed air may be utilized to accomplish the switching without contamination of the carrier stream or the utilization of an expensive gas such as helium.

Referring now to FIG. 10 there is illustrated a schematic diagram of a 2-way valve utilizing the pneumatic memory element of FIG. 1 as a control device. The 2-way valve comprises a pair of chamber means 165 and 166 separated by a pressure responsive means 167 in like manner as the pairs of chambers in the schematic diagram of FIG. 2 are separated. The valve has an input conduit 168 and an output conduit 169, input conduit 168 being arranged in such a manner as to be closed by the pressure responsive means 167 when the pneumatic memory is in the set condition as indicated in the diagram. As has been described when the memory is in the condition illustrated a high pressure exists in the memory output conduit 31 which operates to deflect diaphragm 167 to close the input conduit 168 thereby closing the valve. It is believed further obvious that when the memory is in the reset condition and a low pressure exists in chamber means 165 that pressure responsive means 167 will assume a position such that input conduit 168 is open and flow may occur from input conduit 168 to chamber means 166 and through output conduit 169. -It is further obvious that the direction 'of flow may be interchanged, conduit 169 operating as the input conduit and conduit 168 operating as the output conduit. It is further obvious that other 2-way valves may be operated from either side of the pneumatic memory, those valves connected to memory output conduit 29 will be open when those connected to memory output conduit 31 are closed and vice versa.

It should be understood that the control elements for the pneumatic memories illustrated may take any suitable form such as the 2-way valve illustrated which may be either manually or automatically operated or may take the form of other pneumatic logic elements. It is further obvious that the utilization device need not be a pneurequiring the type of. output and operation supplied by the system. It is also apparent that the pneumatic memory element may be utilized alone or in conjunction with other logic systems and that the valving systems of FIGS. 2; 6, 9 and 10 could utilize appropriate controlling devices other than the memory elements illustrated. It should further be understood that the term pneumatic as utilized herein is intended to encompass all types of gases, gaseous fluids or vapors and is not intended to be limited to air.

While the present invention has been described in detail in connection with two illustrative embodiments of the pneumatic memory and illustrative embodiments of a 4-way and a 2-way valve it should be understood that the novelty of this invention is not Iimited to the specific embodiments illustrated and described but is defined only 7 i pressure responsive means separating said pair of chamber means one from the other;f first and second means for connecting a source of pneu matic pressure to said chamber means, said first means having a difierent flow capacity than said second means;

means connected to one of said pair of chamber means for connecting said one chamber means to a utilization device;

means connected to the other of said pair of chamber means for connecting said other chamber means to a utilization device;

control means connected to said pair of chamber ber means, said pressure responsive means being deflected by said differential pressure to close said first means for connecting the source of pneumatic pressure to the other of said chamber means to maintain said differential pressure within said chamber means.

2. A pneumaticbistable element comprising:

means defining a pair of chambers;

first and second means for connecting a source of pneumatic pressure to each of said pair of chambers, said first means having a larger flow capacity than said second means;-

pressure responsive means separating said pair of chambers and defiectable to a set position and a reset position, said pressure responsive means closing said first means for connecting a source of pneumatic pressure to one of said chambers in said set condition and closing said first means for connecting said source of pneumatic pressure to the other of said chambers in said reset condition;

means connected to said pair of chambers for creating a pressure differential between said chamber means whereby said pressure responsive means may be selectively deflected to said set or said reset position; and

respective output means connected to each of said chambers whereby when said pressure responsive means is in said set condition the pressure in one of said output means is higher than the pressure in the other of said output means and when said pressure responsive means is in the reset condition the pressure in said other output means is higher than the pressure'in said one output means.

3. A pneumatic bistable element having first and second chamber means;

first and second input means for connecting a source of pneumatic pressure to each of said chamber means, said first input means having a larger flow capacity than said second input means;

pressure responsive means separating said chamber means and defiectable to a set position and a reset position, said pressure responsive means closing said first input means connected to one of said chamber means in said set condition and closing said first input means connected to the other of said chamber means in said reset position;

means connected to each of said chamber means for obtaining a pneumatic pressure output from each of said chamber means; and

means for connecting each of said chamber means to a control means whereby a differential pressure may be created between said chamber means by the control means for deflecting said pressure responsive means to said set condition or said reset condition, said pressure responsive means maintaining said differential pressure in said chambers after operation of said control means.

4. A pneumatic memory element having a pair of outputs wherein one of said outputs is at a high pressure when the other is at a low pressure and said other is at a high pressure when said one of said outputs is at a low pressure, said element having a pair of chamber means;

first and second means for connecting a source of pneumatic pressure to each of said pair of chamber means, said first means having a larger flow capacity than said second means;

output means connected to each of said pair of chamber means; pressure responsive means secured between each of said pair of chamber means and defiectable under differential pressure within said pair of chamber means to a set position and a reset position, said pressure responsive means closing said first means for connecting a source of pneumatic pressure to one of said pair of chamber means in said set condition and closing said first means for connecting said source of pneumatic pressure to the other of said pair of chamber means in said reset position; means connected to each of said pair of chamber means and adapted to be connected to control means for momentarily changing the pressure in one of said pair of chamber means for deflecting said pressure responsive means to either said set or reset position, said pressure responsive means remaining in said deflected position due to the differential pressure created in said pair of chamber means by said pressure responsive means closing at least a portion of said means for connecting said source of pneumatic pressure to one of said pair of chamber means until said differential pressure is changed under the influence of a control means. 5. A pneumatic bistable element module having two body elements, each body element having an inner face, first and second chamber means, each of said chamber means having a first and a second portion interconnected by conduit means formed in said body elements, said first portion of said first chamber means being formed in the inner face of one of said body elements, said second portion of said first chamber means being formed in the inner face of the other of said body elements, said first portion of said second chamber means being formed in the inner face of said one body element and said second portion of said second chamber means being formed in the inner face of said other body element;

inlet conduit means formed in said one body element for connecting a source of pneumatic pressure to said first portion of each of said chamber means;

output conduit means formed'in said other body element connected to the second portion of each of said chamber means; first pressure responsive means sandwiched between said inner faces of said body elements and separating said first portion of said first chamber means from the second portion of said second chamber means;

second pressure responsive means sandwiched between said inner faces of said body elements and separating said first portion of said second chamber means from the second portion of said first chamber means;

said first and second pressure responsive means having a set condition and a reset condition, said first pressure responsive means closing said inlet conduit means to said first portion of said first chamber means in the set condition and said second pressure responsive means closing said inlet conduit means in said first portion of said second chamber means in the reset condition whereby a differential pressure may be maintained between said first and second chamber means in each of said set and reset conditions; and control inlet conduit means formed in said one body element for connecting said pair of chamber means to a control device for momentarily creating a differential pressure between said chamber means whereby said pressure responsive means may be deflected to either said set or reset condition.

6. A pneumatic bistable element module having two 'body elements, each body element including an inner face, first and second pneumatic output conduits in one of said body elements, and first and second states wherein the pressure in said first output conduit is at a high level and the pressure in said second output conduit is at a low level in said first state and the pressure in said second output conduit is at a high level and the pressure in said first output is at a low level in said second state;

said module further having first, second, third, fourth,

fifth, sixth, seventh, eighth, ninth and tenth chamber means, said second, fourth, sixth, eighth chamber means and first portions of said ninth and tenth chamber means formed in the inner face of one of said body elements, and said first, third, fifth, seventh chamber means and second portions of said ninth and tenth chamber means formed in the inner face of the other of said body elements;

first, second, third, fourth pressure responsive means sandwiched between said inner faces and separating respectively said first and second, third and fourth, fifth and sixth, and seventh and eighth chamber means;

fifth and sixth pressure responsive means sandwiched between said inner faces and separating said ninth and tenth chamber means;

each of said pressure responsive means being deflectable under a differential pressure between said chamber means to a set condition and a reset condition;

first conduit means formed in said one "body element for connecting said fourth, sixth, ninth and tenth chamber-means to a source of pneumatic pressure;

first conduit means formed in said other body element for interconnecting said first, third and tenth chamber means;

second conduit means formed in said other body element for interconnecting said fifth, seventh and ninth chamber means;

second conduit means formed in said one body element for interconnecting said sixth chamber means, said second chamber means and one of said output conduits, said second conduit means in said one body element forming a pneumatic input means to said second chamber means;

third conduit means formed in said one body element for interconnecting said fourth chamber means, said eighth chamber means and the other of said output conduits, said third conduit means in said one body element forming a pneumatic input to said eighth chamber means; fourth conduit means formed in said one body element connected to said second and eighth chamber means for bleeding said chamber means to a low pressure area;

control means connected to said ninth and tenth chamber means and adapted to selectively and momentarily decrease the pressure in each of said chamber means;

whereby upon actuation of said control means said pressure responsive means may be selectively deflected to said set condition and remain so deflected until deflected to said reset condition by said control means; said first, second and fifth pressure responsive means closing the pneumatic pressure inlet to said second, fourth and ninth chamber means in said set condition and said third, fourth and sixth pressure responsive means closing the pneumatic pressure inlet to said sixth, eighth and tenth chamber means in said reset condition whereby the differentialpressure created between each of said chamber means is maintained after'said control means is mo- 1'6 mentarily actuated whereby the differential, pressure at the outputs of the device is maintained.

7. A pneumatic 4-:way valve comprising:

two body elements, each body element'having an inner face;

first, second, third and fourth chamber meansformed in the inner face of one of said body elements, each chamber means having an input and an output and a pressure responsive means 7 sandwiched between said inner faces of said body elements and adapted to close the input to its respective chamber;

a pair of valve output conduit means formed in said one body element;

conduit means formed in said one body element interconnecting the input of said first chamber means, the output of said third chamber means and one of said valve output means;

conduit means formed in said one body element interconnecting the input of said fourth chamber means,

the output of said second chamber means and the other of said valve output means;

conduit means formed in said one body element for connecting the input of said second and third chamber means to a source of pneumatic pressure; and

control means connected to said pressure responsive means via conduits formed in the other of said body elements for selectively deflecting the pressure responsive means of said first and second chambers or said pressure responsive means of said third and fourth chambers whereby either of said valve output means may be connected to a source of pneumatic pressure. p

8. A 4-way valve comprising:

two body elements, each body element having an inner face;

first, second, third and fourth chamber means formed in the inner face of one of said body elements, each.

chamber means having an input means and an output means;

each of said chambers including means disposed between said inner faces of said body element-s for closing said input to the respective chambers;

means formed in said one body element for connecting the input of said second and third chamber means to a'source of pneumatic pressure;

a pair of valve output means;

means formed in said one body element for connecting the input of said first chamber means with the output of said third chamber means and one of said valve output means;

means formed in said one body element for connecting the input of said fourthfchamber means with the output of said second chamber means and the other of said valve outputs; a

means formed in said one body element for connecting said first and fourth chamber means to a low pressure area; and 7 control means, connected to conduit means formed in the other of said body elements, for selectively operating said means included in each of said chambers for closing the inputs thereto, said control means selectively operating the control means in said first and second chambers or the control means in said third and fourth chambers whereby either one of said valve output means may be connected to a source of pneumatic pressure while the other is connected to a low pressure area.

9. A 4-way pneumatic valve comprising:

two body elements, each body element having an inner face;

first, second, third and fourth chamber means formed in the inner face of one of said body elements, the inner face of the other of said body elements covering said chamber means, each chamber means having an input and an output;

means formed in said one 'body element for connecting a source of pneumatic pressure to the input of said second and third chamber means;

means formed in said one body element for connecting the output of said first and fourth chamber means to a low pressure area;

first and second valve output means;

means formed in said one body element interconnecting the input of said first chamber means, the output of said third chamber means and said first valve output;

means formed in said one body element interconnecting the input of said fourth chamber means, the output of said second chamber means and said second valve output means; and

control means connected to said chamber means via conduit means formed in said other body element for closing selectively the input to said first and second chamber means or the input to said third and fourth chamber means whereby eitherof said valve outputs may be connected to a source of pneumatic pressure while the other is connected to a low pres sure area.

10. A pneumatic 4-way valve system comprising:

two body elements each having an inner face, said body elements being joined at said inner faces;

means formed in the inner face of at least one of said body elements, said means defining a plurality of chambers each having a pressure responsive element defiectable to a set and a reset condition;

power source means connected via conduits formed in said one body element to a pair of said plurality of chambers for supplying pressure thereto;

control means connected via conduits formed in said one body element to said pair of chamber means for controlling the differential pressure therebetween to set or reset said pressure responsive means;

output means connected to each of said chamber means for connecting said pair of chamber means to selected ones of the other of said plurality of chamber means whereby the output of said pair of chamber means operates to set and reset the pressure responsive means in said other chamber means;

means formed in said one body element connecting a source of pressure to said other chamber means, said means being closed by said pressure responsive means in one of said set or reset conditions; and

means formed in said one body element connected to said other of said plurality of chamber means for providing an output from said chamber means whereby said control means may operate to connect or disconnect said source of pressure to said output means.

11. A pneumatic valve system comprising:

two body elements having an inner face;

first, second, third and fourth chamber means formed in the inner face of one of said body elements, each chamber means having a pair of conduits, formed in said one body element, connected thereto and a pressure responsive means adapted on deflection to close one of said conduits to its respective chamber;

a pair of valve output means;

means formed in said one body element interconnecting one of said conduits of said first and third chamber means and one of said valve output means;

means formed in said one 'body element interconnecting one of said pair of conduits of said second and fourth chamber means and the other of said valve output means;

a source of pneumatic pressure connected to the other of said pair of conduit means of said second and third chamber means; and

control means for selectively deflecting a pressure responsive means of said first and second chamber means or said pressure responsive means of said third and fourth chamber means whereby either of said valve output means may be connected to said source of pneumatic pressure.

12. A bistable element module comprising:

two body elements, each body element having an inner face;

first and second chamber means formed in said inner face of one of said body elements, each of said chamber means having first and second inlet means;

first conduit means formed in said one body element for connecting a source of fluid under pressure to said first inlet means of said first and second chamber means;

second conduit means formed in said one body element for connecting a control device to said second inlet means of said first and second chamber means;

third and fourth conduit means formed in said one body element for connecting said module to .a utilization device;

first and second chamber means formed in said inner face of the other of said body elements, said first and second chamber means in said one body element corresponding, respectively, to said first and second chamber means in said other body element when said body elements are joined .at said inner faces;

output conduit means, connected to said first and second chamber means in said other body element, formed in said other body element;

flat, resilient diaphragm means, said body elements being assembled with said diaphragm means interposed between said inner faces and separating said first chamber means in said one body element from said first chamber means in said other body element and said second chamber means in said one body element from said second chamber means in said other body element;

conduit means in both said body elements for interconnecting said first chamber means in said one body element with said second chamber means in said other body element and said second chamber means in said one body element with said first chamber means in said other body element, said control device being momentarily operable to create a pressure difference between (i) said first chamber in said one body element and said second chamber in said other body body element and (ii) said second chamber in said one body element and said first chamber means in said other body element;

means formed in said body element interconnecting said output conduit means with said third and fourth conduit means, said diaphragm means having a set and a reset condition, said diaphragm means in said set condition closing said first inlet means in said first chamber of said one body element when said control device is momentarily operated and in said reset condition closing said first inlet means in said second chamber means of said one body element when said control device is again momentarily operated, whereby, in said set condition, the pressure in said third conduit means is at a high level and the pressure in said fourth conduit means is at a low level and, in said reset condition, the pressure in said third conduit means is at a low level and the pressure in said fourth conduit means is at a high level.

13. A bistable logic element module comprising:

a body including first and second mating halves, each said half having an inner face;

first, second, third, fourth, fifth and sixth chambers formed in said inner face of said first half of said body, each of said first, second, third, fourth, fifth and sixth chambers having first and second port means;

seventh, eighth, ninth, tenth, eleventh and twelfth chambers formed in said inner face of said second half of said body, said first, second, third, fourth, fifth and sixth chambers in said first half of said body corresponding, respectively, to said seventh, eighth,

ninth, tenth, eleventh and twelfth chambers in said second half of said body when said halves are joined at said inner faces;

pressure responsive means, said body being assembled with said pressure responsive means interposed between said inner faces and separating said chambers formed in said first half of said body from said chambers formed in said second half of said body;

first conduit means in said first body half for connecting said first port means of said first, second, fourth and fifth chambers with a source of fluid under pressure;

second conduit means in said first body half for connecting said second port means of said first and second chambers with control means whereby the pressure in said first or second chamber may be momentarily reduced;

third conduit means in said first body half for connecting said second port means of said third and sixth chambers with a source of low pressure;

fourth conduit means in said first body half for connecting said second port means of said fourth and fifth chambers with a utilization device;

fifth and sixth conduit means in said first body half for connecting said first port means of said third and sixth chambers with said second port means of said fourth and fifth chambers, respectively;

first conduit means in said second body half for interconnecting said seventh, tenth and twelfth chambers;

second conduit means in said second body half for interconnecting said eighth, ninth and eleventh chambers;

conduit means in said first andsecond body half for interconnecting said second port means of said first chamber with said eighth chamber and said second port means of said second chamber with said seventh chamber, whereby, upon momentary actuation of said control means, said pressure responsive means may be selectively deflected to a set condition and remain so deflected until deflected to a reset condition by another momentary activation of said control means; in said set condition, said pressure responsive means interrupting communication between said first and second port means of said first, fourth and sixth chambers, said utilization device thereby operating in a first mode, and in said reset condition, said pressure responsive means interrupting communication between said first and second port means of said second, third and fifth chambers, said utilization device thereby operating in a second mode.

References Cited UNITED STATES PATENTS 3,057,551 10/1962 Etter 137--81. 5 3,080,887 3/.1963 Brandenberg 137596 3,151,623 10/1964 Riordan 23520 1 3,156,157 10/1964 Smith 235201 3,168,898 2/1965 Samet 23520l 3,202,179 8/1965 Vockroth 235-201 M. CARY NELSON, Primary Examiner.

' W. R. CLINE, Assistant Examiner. 

3. A PNEUMATIC BISTABLE ELEMENT HAVING FIRST AND SECOND CHAMBER MEANS; FIRST AND SECOND INPUT MEANS FOR CONNECTING A SOURCE OF PNEUMATIC PRESSURE TO EACH OF SAID CHAMBER MEANS, SAID FIRST INPUT MEANS HAVING A LARGER FLOW CAPACITY THAN SAID SECOND INPUT MEANS; PRESSURE REPONSIVE MEANS SEPARATING SAID CHAMBER MEANS AND DEFLECTABLE TO A SET POSITION AND A RESET POSITION, SAID PRESSURE RESPONSIVE MEANS CLOSING SAID FIRST INPUT MEANS CONNECTED TO ONE OF SAID CHAMBER MEANS IN SAID SET CONDITION AND CLOSING SAID FIRST INPUT MEANS CONNECTED TO THE OTHER OF SAID CHAMBER MEANS IN SAID RESET POSITION; MEANS CONNECTED TO EACH OF SAID CHAMBER MEANS FOR OBTAINING A PNEUMATIC PRESSURE OUTPUT FROM EACH OF SAID CHAMBER MEANS; AND MEANS FOR CONNECTING EACH OF SAID CHAMBER MEANS TO A CONTROL MEANS WHEREBY A DIFFERENTIAL PRESSURE MAY BE CREATED BETWEEN SAID CHAMBER MEANS BY THE CONTROL MEANS FOR DEFLECTING SAID PRESSURE RESPONSIVE MEANS TO SAID SET CONDITION OR SAID RESET CONDITION, SAID PRESSURE RESPONSIVE MEANS MAINTAINING SAID DIFFERENTIAL PRESSURE IN SAID CHAMBERS AFTER OPERATION OF SAID CONTROL MEANS. 